Kotaku :We've previously seen how Halo 3's Forge can be used as a canvas by the artistically included. And while the above image is certainly not the first "erotic" images made with Forge level editor by a damn sight. (Hey, give the plebs the ability to create, and you betcha, they'll whip up naughty bits!) But these are the first MAXIMUM RISKY Japanese anime-style ones we've seen - then again, we haven't exactly been looking. They, of course, were made by lining up weapons.
(Warning, maybe NSFW)